Should I Retake?

<p>I took the SAT in March and got:
CR 710
M 790
W 690</p>

<p>I'm looking at some ivies(Yale, Brown, Penn) & Duke as my top choices. I doubt I can do better at CR, maybe 10-20 points, but I think I could do better on W. I was thrown off by the essay and there's no guarantee it will be better the next time, even if I prepare more. On the practice tests, I could get around 750, but this didn't factor in my rather... awful essay (I got 71 subscore on this once w/ -3). So, my question is should I retake? I can improve slightly, but I'm in the range for all except maybe Yale (depending on where you look their lower range is 700 or 690). And from what I know, once you're in the range, you're fine. Would you agree?
(Sorry this is another one of those posts, but I'm interested to see if this will actually help my chance of admission. I really don't want to sit through another 5 hour test!!)</p>